Norman - looks like Keith is on the right track. Unfortunately, your choice of scarlet back drop does hinder the glass colours somewhat, and not sure that I can make out the grey that you mention, although if that is what you are seeing then wouldn't doubt you. Just for interests sake, can quote from Mark Hill's book which mentions that Zemek's earlier work is characterized by prunts/projections which carried the colour - as opposed to his later designs which apparently had the colour placed more in straps or stripes down the glass, and which lacked the prunts. This Rhapsody range was massively popular, apparently. Anyway, good piece.
Reference: Mark Hill - "Hi Sklo Lo Sklo - Post War Czech Glass Design - 2008.